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The development of photoacoustic tomography system for biological imaging objects has been carried out. The use of 532 nm green diode lasers as a radiation source because of their low cost, compact size, high pulse repetition rate, and high output power. An Omni Behringer ECM 8000 condenser microphone was amplified with a Behringer soundcard to detect sounds with frequencies up to 20 kHz. The system was connected to a laptop that has been installed LabView software, which functions for interpretation and storage of data in x/x format and the results of 2-dimensional images. The system was used to image the chicken's aorta that was given fat in it and placed in paraffin media. Obtained a duty cycle to image objects optimally at 50% and a frequency of 19 kHz. The difference in the results of the aortic image and fat tissue is seen when the green dye is added to the sample to increase image contrast. This is because the absorption of aortic and fatty tissue is not optimal at a wavelength of 532 nm. The addition of roasted cereal as a contrast agent that can increase the highest level of sample intensity is the type of roasted white rice with an average TI value of - 71.3998 dB. It is hoped that in the future the system can be developed for tissue imaging with the aim of early detection of atherosclerotic disease in humans. [ABSTRACT FROM AUTHOR]

Biomedical image is generally noisy and little blur due to the physical mechanisms of the acquisition process, so one of the common degradations in biomedical image is their noise and poor contrast. The idea of biomedical image enhancement is to improve the quality of the image for early diagnosis. In this paper we are using Wavelet Transformation to remove the Gaussian noise from biomedical images: Positron Emission Tomography (PET) image and Radiography (Radio) image, in different color spaces (RGB, HSV, YCbCr), and we perform the fusion of the denoised images resulting from the above denoising techniques using add image method. Then some quantive performance metrics such as signal-to-noise ratio (SNR), peak signal-to-noise ratio (PSNR), and Mean Square Error (MSE), etc. are computed. Since this statistical measurement helps in the assessment of fidelity and image quality. The results showed that our approach can be applied of Image types of color spaces for biomedical images. [ABSTRACT FROM AUTHOR]

The stiffness of the uterine cervix changes during pregnancy, significantly softening at term. A pathologically rapid softening can result in preterm birth. ShearWave Elasticity Imaging (SWEI) methods can be used to track these changes. Diffculties of in vivo human research during pregnancy motivate the study of animal models with anatomy and physiology similar to humans. This work presents preliminary results of the use of SWEI methods to assess cervical stiffness changes during pregnancy in a rhesus macaque non-human primate (NHP) model. Pregnant NHP subjects are being scanned during two consecutive menstrual cycles before pregnancy and five times between weeks 4 to 23 after conception and once two weeks after delivery. Shear waves are remotely induced with an Acoustic Radiation Force Impulse excitation within regions of interest (ROIs) centered in the uterine end of cervix. Shear wave speed (SWS) was quantified with different estimators and at various ROI locations to choose the more consistent and precise estimates. From 25 subjects currently enrolled, 8 have successfully completed the study. At late pregnancy, SWS values significantly decreased to less than 40% of their pre-pregnancy values, and recovered two weeks after delivery. SWS changes in the same subject at early pregnancy compared to pre-pregnancy and late-pregnancy values were statistically significant. Our results motivate further investigation of SWEI to track cervical softening during pregnancy in the NHP model. [ABSTRACT FROM AUTHOR]

A method for determining the pupil boundary in the image of eye is proposed. The method is based on examining connected components of binarized image. The components are first sorted according to probability to contain pupil, which is estimated from their inertia moments by empirically derived rules. Hough transform is applied to border of the component and outlines the center of most pronounced circular arc. If center hypothesis is strong enough the histogram of distances of border points to this center is built. If pronounced maximum exists on the histogram it means that a circle or an arc is present in this component, which is taken for pupil boundary. The method benefits from both stability of Hough approach and small number of pixels detected as boundaries of connected components. Tests were performed with several iris image databases from public domain. [ABSTRACT FROM AUTHOR]

A framework of methods for iris location and segmentation in eye image is presented. The basic idea of the framework is that in the beginning stages the most general features should be detected and then gradually refined to evaluate more detailed object description in the ending stages. Each iris parameter is revised several times. System starts with approximate detection of eye center position followed by approximate simultaneous detection of inner and outer boundaries of iris region. If one of the boundaries is not detected, an additional attempt to locate it is performed with the help of alternative method. Finally precise borders are detected at last steps of processing by specially designed methods. The system capability is verified with public domain databases of iris images, as well as in international IREX NIST test. [ABSTRACT FROM AUTHOR]

Development of video-fluorescence and spectral equipment for silicon nanoparticles detection in biological objects. [ABSTRACT FROM AUTHOR]

We present here some miniaturised devices designed for the detection of nanorods in water and blood media. The devices use light emitting diodes as monochromatic light sources and Si photodiodes for detection. Devices working on transmission mode are able to detect nanorods concentration below micrograms/litre. Sensitivity is reduced is one or of magnitude for nanorods in blood. We show detection of low nanorods concentration with devices working in reflection mode, opening the possibility to perform direct imaging of nanorods in vivo. The optima condition for detection and resolution limits are also discussed. [ABSTRACT FROM AUTHOR]

: Luminescent silicon nanoparticles particles produced by laser pyrolysis are considered as possible alternative to replace toxic Quantum Dot in bioimaging applications. However, these nanoparticles are fully oxidized when kept in water, therefore, the luminescent silicon core must be be protected from oxidation. The Si nanoparticles were embedded in monodisperse silica beads (∼50 nm) produced in microemulsion. The silica beads provide protection of the silicon core and allow stability of the photoluminescence over time. They are well dispersed in water and biological medium with a colloidal stability of several days. [ABSTRACT FROM AUTHOR]

Various DNA-based structures (single-, double-, triple-stranded and quadruplex-DNA) were characterized using non-contact atomic-force microscopy on two substrates: modified highly-oriented pyrolitic graphite (HOPG) and mica. Deposition on mica, a conventional substrate used in studies of bio-molecules, results in strong deformation of all above types of molecules while deposition on modified HOPG affects the morphology of DNA much less compared to mica. This is demonstrated by a larger measured height of the DNA molecules deposited on HOPG, as compared to mica, and an increased flexibility of the molecules, evidenced by a shorter molecular end-to-end distance on HOPG. The estimated heights of the triplex and the quadruplex DNA measured on HOPG are similar to the diameter of these molecules in liquid. We thus conclude that modified HOPG is a substrate more suitable than mica for AFM characterization of DNA morphology. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Soft X-ray microscopy employs the natural absorption contrast between water and protein in the 2.34 - 4.38 nm wavelength region with a resolution down to 30 nm. The large depth of focus of the Fresnel zone plates used as X-ray objectives permits tomographic reconstruction based on the microscopic images. High-resolution images require a high specimen radiation dose, and a large number of images taken at different viewing angles is needed for tomographic reconstruction. Therefore, cryo microscopy is necessary to preserve the structural integrity of hydrated biological specimens during image acquisition. The cryo transmission X-ray microscope at the electron storage ring BESSY I (Berlin) was used to obtain a tilt series of images of the frozen-hydrated green alga Chlamydomonas reinhardtii. The living specimens were inserted into borosilicate capillaries, then rapidly cooled by plunging into liquid nitrogen. The capillary specimen holders allow image acquisition over the full angular range of 180°. The reconstruction shows details inside the alga down to 60 nm size and conveys a detailed impression of the specimen structure. This technique is expected to be applicable to a wide range of biological specimens, such as the cell nucleus, It offers the possibility of imaging the three-dimensional structure of hydrated biological specimens close to their natural living state. [ABSTRACT FROM AUTHOR]

The development of two types of X-ray microscopy applying to the organic objects investigation (biological samples and polymer matrix) is reported. Polymer track membranes were investigated using Schwarzchild X-ray microscope with 20 nm wavelength. Pore diameters down to 0.2 μm were clearly imaged. Contact X-ray microscopy at 0.229 nm wavelength was used to obtain clear images of inner structure of native biological samples. High contrast together with the high resolution (about 2-3μm) allowed us to use this method for quantitative analysis of demineralization process taking place in the skeleton of amphibious after several weeks of weightlessness on biosputnik board. [ABSTRACT FROM AUTHOR]

To image molecule or element distribution in a cell, XANES of such biomolecules in a cellular environment give direct information about photon energy choosing for imaging. This study describes XANES of dried Chinese hamster ovary cells in the pellet form at the N, O, P and S-K absorption edges. In addition, XANES of dried pellet of nuclear and mitochondrial traction were measured at the N and O-K edges. At the N-K edge XANES of cells had peaks at the identical energies of isolated DNA and histone, indicating that XANES peaks of biomolecules arc insensitive lo the cellular environment. The similar results were obtained for the cases of the P-K and S-K edges: XANES profile of cells at the P-K edge is likely to be a mixed pattern of DNA and related molecules including nucleotides, and the profile at the S-K edge could be explained by the superposition of those of SH and SS compounds. However, at the O-K edge, XANES of cells and nuclei exhibited the same peak slightly shifted to the higher energy compared with that in XANES of histone. This result indicates that for molecule or element imaging of a specimen, XANES should be measured under the specimen environment. [ABSTRACT FROM AUTHOR]

Intracellular mapping of elements was performed for Cd or Hg loaded mammalian cells. X-ray contact microscopy with an electronic zooming tube were used for cell imaging at the resolution of 0.5 μm. The mapping was obtained by the subtraction between images taken at two different wavelengths. For both elements, pair of the wavelengths at 8.21 nm and 4.48 nm was adopted, because the absorption coefficients of Cd and Hg at 8.21 nm are smaller than those at 4.48 nm, while those of major elements in biological components such as C, N and O exhibit opposite nature. Subtracted data were compared with those for non-loaded cells. The results suggest that the present method is valuable for a new approach to image some kinds of elements such as Cd and Hg that have no absorption edge or have the absorption edge overlapped with those of major elements in this wavelength region. [ABSTRACT FROM AUTHOR]

Soft x-ray microscopy is now routinely capable of imaging biological specimens with resolutions that are five times better than the best visible light microscopes (≤ 50 nm). However, for biological labeling the only options developed for x-ray microscopy have been silver enhanced gold probes that can be used with both scanning and wide field CCD microscopes, such as XM-1 at the Advanced Light Source (ALS), and luminescent lanthanide probes that necessitate a scanning microscope (SXM). To add to the arsenal of useful x-ray biological probes, we have begun the development of labels that rely on the L-edge absorption lines of vanadium Vanadium is especially attractive as a biological contrast reagent because it has two strong absorption lines at energies that range from 8sim;512 to 525 eV just below the oxygen K-edge, which makes it an ideal material for imaging in the water window. In this report, we present our initial findings on the application of vanadium for biological labeling. Fixed NIH 3T3 cells grown on silicon nitride windows were incubated with vanadyl sulfate and in some cases basified with triethylamine. After vanadium treatment of the cells, they were thoroughly rinsed and then imaged using XM-1 above and below the vanadium 516 eV resonance. Vanadium staining was clearly visible around and in the cells. These findings suggest that bioconjugated vanadium clusters could provide sufficient x-ray contrast to be used as biological probes. [ABSTRACT FROM AUTHOR]

Neuronal cultures show a rich repertoire of spontaneous activity. However, the mechanisms that relate a particular network architecture with a specific dynamic behavior are still not well understood. In order to investigate the dependence of neuronal network dynamics on architecture we study spontaneous activity in networks formed by interconnected aggregates of neurons (clustered neuronal networks). In the experiments we monitor the spontaneous activity using calcium fluorescence imaging. Network's firing is characterized by bursts of activity, in which the clusters fire sequentially in a short time window, remaining silent until the next bursting episode. We also investigate perturbations on the connectivity of the network. We mainly focus in physical damage. In some cases we observe important changes in the collective activity of the network, while in other cases some dynamic motifs are preserved, hinting at the existence of dynamic robustness. [ABSTRACT FROM AUTHOR]

At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work. [ABSTRACT FROM AUTHOR]

Iron oxide Nanoparticles represents promising nanocarrier for magnetic resonance imaging (MRI), targeted drug and gene delivery. In our study we investigated the interaction between lung alveolar epithelial cells and iron oxide NPs coated with L-Dihydroxyphenylalanina (L-Dopa)-TRITC. Our data suggest that particles crossed the plasma membrane with an energy-dependent process. [ABSTRACT FROM AUTHOR]

The recent observation of strong amplification on multikilovolt Xe(L) hollow atom transitions in the ∼2.8 A spectral region can be seen as a consequence of the combination of (1) a new concept for amplification that involves the creation of a highly ordered state combining ionic, plasma, and coherent radiative components and (2) the use of two recently discovered (c. ∼1990) forms of radially symmetric energetic matter, namely, hollow atoms and self-trapped plasma channels. This approach enables the demanding power densities necessary for x-ray amplification (∼1019 W/cm³) to be reached under conditions for which (α) the effective phase space volume of the interaction is profoundly limited and (β) the energy transfer is radiation dominated. A leading application will be the realization of a new mode of microimaging of living biological matter having a spatial resolution ∼1000-fold superior to conventional light microscopy. [ABSTRACT FROM AUTHOR]